Bend alignment type liquid crystal display apparatus

Abstract

A liquid crystal display apparatus includes a liquid crystal layer sealed between a first substrate and a second substrate opposed to each other. Inner surfaces of the first and second substrates have been subjected to aligning treatment to splay-align liquid crystal molecules. The liquid crystal display further includes electrodes formed on the inner surfaces of the first and second substrates to generate an alignment transition electric field to cause the liquid crystal molecules to transit from splay alignment to bend alignment. The alignment transition electric field includes a vertical electric field in the thickness direction of the liquid crystal layer, and a horizontal electric field in a direction parallel to the inner surfaces of the first and second substrates to twist the liquid crystal molecules between the substrates.

1. A liquid crystal display apparatus comprising:
 a liquid crystal layer sealed between a first substrate and a second substrate opposed to each other, inner surfaces of the first and second substrates having been subjected to aligning treatment to align liquid crystal molecules in a splay configuration; and 
 a plurality of electrodes formed on the inner surfaces of the first and second substrates to generate an alignment transition electric field to cause the liquid crystal molecules to transition from splay alignment to bend alignment, the alignment transition electric field comprising a vertical electric field in a thickness direction of the liquid crystal layer and a horizontal electric field in a direction parallel to the inner surfaces of the first and second substrates to twist the liquid crystal molecules between the first and second substrates; 
 wherein the electrodes comprise first electrodes and second electrodes formed on the inner surface of the first substrate to be insulated from each other to generate the horizontal electric field in a direction substantially parallel to the inner surface of the first substrate, and a third electrode formed on the inner surface of the second substrate to generate the vertical electric field in the thickness direction of the liquid crystal layer with respect to at least one of the first and second electrodes; 
 wherein each first electrode comprises a conductive film with an area corresponding to a pixel to form one display element of the liquid crystal display apparatus, and each second electrode comprises a transparent electrode formed to overlap the first electrode via an insulating film and having an area smaller than the area of the first electrode, to generate the horizontal electric field between the first electrode and an edge of the second electrode which overlaps the first electrode. 
 
     
     
       2. An apparatus according to  claim 1 , wherein each second electrode comprises a comb-shaped conductive film formed on the first substrate and patterned into a comb shape including a plurality of electrode finger portions extending in one direction. 
     
     
       3. An apparatus according to  claim 2 , wherein the electrode finger portions of the comb-shaped conductive film extend in a direction intersecting a direction of aligning treatment of the liquid crystal display apparatus. 
     
     
       4. A liquid crystal display apparatus comprising:
 a first substrate and a second substrate arranged to oppose each other at a predetermined gap; 
 a plurality of first electrodes formed on an inner surface of the first substrate; 
 a plurality of second electrodes, formed on the inner surface of the first substrate to be insulated from the first electrodes, to generate a horizontal electric field in a predetermined first direction substantially parallel to the inner surfaces of the first and second substrates with respect to the first electrodes; 
 a first alignment film which is formed on the inner surface of the first substrate to cover the first and second electrodes and which has been subjected to aligning treatment in a second direction intersecting the first direction of the horizontal electric field; 
 a third electrode, formed on the inner surface of the second substrate to oppose the first and second electrodes, to generate a vertical field, at least with respect to the second electrodes, in a thickness direction of the gap between the first and second substrates; 
 a second alignment film which is formed on the inner surface of the second substrate to cover the third electrode and which has been subjected to aligning treatment in a direction which is parallel to the second direction of the first alignment film and the same as the direction of the aligning treatment of the first alignment film; 
 a liquid crystal layer sealed in the gap between the first and second substrates and including liquid crystal molecules aligned in a splay configuration in accordance with alignment regulating forces of the first alignment film and the second alignment film; and 
 a pair of polarization plates provided respectively outside the first and second substrates; 
 wherein the first, second, and third electrodes formed on the inner surfaces of the first and second substrates are adapted to generate an alignment transition electric field to cause the liquid crystal molecules to transition from splay alignment to bend alignment, the alignment transition electric field comprising the vertical electric field in the thickness direction of the gap between the first and second substrates and the horizontal electric field in the predetermined first direction substantially parallel to the inner surfaces of the first and second substrates to twist the liquid crystal molecules between the first and second substrates; and 
 wherein each first electrode comprises a transparent conductive film with an area corresponding to a pixel to form one display element of the liquid crystal display apparatus, and each second electrode comprises a transparent conductive electrode formed to overlap the first electrode through an insulating film and having an area smaller than the area of the first electrode, to generate the horizontal electric field between the first electrode and an edge of the second electrode which overlaps the first electrode. 
 
     
     
       5. An apparatus according to  claim 4 , wherein each second electrode comprises a comb-shaped conductive film formed on the first substrate and patterned into a comb shape including a plurality of electrode finger portions extending in one direction. 
     
     
       6. An apparatus according to  claim 5 , wherein the electrode finger portions of the comb-shaped conductive film extend in a direction intersecting a direction of aligning treatment of the liquid crystal display apparatus.